1. Technical Field
The present invention relates to a projector and a display device, and in particular to a projector and a display device each having a temperature control structure with good efficiency of an optical element and being superior in thermal reliability.
2. Related Art
A projector in which a liquid crystal light valve is irradiated with light from a light source such as a high pressure mercury lamp or xenon lamp, and an image formed on the liquid crystal valve is enlargedly displayed on a screen by a projection lens or the like has been put into practice. While increase in brightness of the display image, namely increase in output of the light source, is in progress in order for making a projection image be viewed on a large screen even in a bright room, downsizing of the projector and the liquid crystal light valve is also in progress in order for making it easy to transport and handle the projector device. Therefore, the light with extremely high intensity has been getting to enter the optical elements positioned on in the illumination or on the projection light path, such as a liquid crystal light valve, a polarization plate, or a polarization conversion element. However, since a part of or a large proportion of the incident light is converted into heat in these optical elements, degradation or deterioration of the optical characteristics and shorter operation lives of the optical elements caused by heat charge of the optical elements have become big problems.
In order for preventing the heat charge of the optical elements, there are invented measures such that the optical elements are cooled using a large sized air-cooling fan with a high cooling capability, or that a crystalline substrate with high thermal conductivity (i.e., a heat radiation property) such as sapphire is used as the substrate for holding the polarization plate or the polarization conversion element (e.g., JP-A-11-231277 and JP-A-2110-318359).
However, in the former measure, there are problems that it is incompatible with downsizing of the projector device, and further, that increase in noise in accordance with increase in cooling capability can hardly be avoided. Further, in the latter measure, there is a problem that, since the heat is conducted and radiated naturally (in an unforced manner) in accordance with the heat distribution gradient caused in the crystalline substrate, sufficient heat radiation is not achievable in the case in which the amount of heat generation is extremely large, thus the heat charge cannot sufficiently be prevented.